Ripper apparatus and method of using same



SePt- 12, 1967 M. D. Ho-sTETrER 3,341,253

RIPPER APPARATUS AND METHOD OF USING SAME Filed NOV. 13, 1964 3Sheets-Sheet 1 Sept. l2, 1967 M. D. HosTErrER 3,341,253

RIPPER APPARATUS AND METHOD OF USING SAME Filed Nov. 13, 1964 3Sheets-Sheet 2 Sept. l2, 1967 M. D. HOSTETTER INVENTO Filed NOV. l5,1964 Afasfffffe United States Patent O Filed Nov. 13, 1964, Ser. No.410,856 30 Claims. '(Cl. 299-10) This invention relates to ripping ofterrain formations and more particularly to an improved crawler typetraction means and to an improved ripper adjustably coupled thereto anddesigned to penetrate the terrain automatically both with and withoutthe use of power-applied penetrating forces in addition to thosegenerated as an incident to forward movement of the traction vehicle.The invention also includes an improved shank, tooth and retainer means,taken separately and in combination.

Modern day excavating operations present serious problems as respectsprovisions of satisfactory and elfective means for loosening widelyvarying types of terrain sufiiciently for handling by earth-handlingequipment. Many proposals and constructions have been presentedheretofore intended to cope with these problems but all are subject toserious shortcomings and defects sought to be obviated by the presentinvention. Typical of these problems and shortcomings evidenced by priorequipment are the following.

For example, it is found that the penetration of ripper equipment intorock or compacted formations is difficult and requires allocation ofsubstantial portions of the available power to mere advance of thehauling equipment. Additionally and seriously, power applied in effortsto press the ripper into the ground, according to prior proposals,invariably materially reduces the tractive effort eectiveness of thehauling vehicle since the reaction to the penetrating forces serves tolift the vehicle away from the ground. Furthermore, it is found that theapplication of power-driven penetrating forces must be continued evenafter the ripper has been forced to a desired depth in order to keep theripper teeth from again rising out of the surface.

An additional defect is that prior ripper equipment has been soconstructed that the ripper tooth is not uniformly and properly posturedrelative to the horizontal when adjusted to different operating levelswith the result that the tooth is not uniformly eiiicient in its variousadjusted positions.

Another shortcoming of prior ripper equipment has been the lack of aripper tooth having acceptable and satisfactory life and so designed asto have a wear pattern corresponding generally to the surface contour ofthe new tooth with the result that prior ripper teeth do not retaintheir shape and contour as wear progresses in use.

Typical ripper teeth as heretofore commonly designed are characterizedby a relatively short forward pointed end in combination with atriangular socket opening rearwardly and adapted to telescope over acomplementally shaped triangular nose piece of the supporting shank.Many problems are involved in the manufacture and use of such a tooth.These include the diiculties involved in the manufacture by casting orforging the mounting sockets of the teeth within acceptable tolerancevariations with the result that many teeth have sockets even too smallfor proper assembly over the nose piece or are so large as to be looseand ill-fitting. In consequence, many attempts have been made to providean elfective means for holding the tooth locked in a desired position onthe nose piece.

A further and serious shortcoming of prior tooth derice sign involvesinsurmountable problems in the proper heat treatment to avoid locking insevere stresses as an incident of heat treatment. These problems in manyinstances, are closely connected with the aforedescribed triangularsocket design which is unavoidably associated with widely varying wallthicknesses and heat reservoirs in the thicker portions of the tooth. Inother words, it is found that portions of the tooth walls forward of thesocket cool much more slowly during quenching than do other portions ofthe tooth and constitute heat reservoirs. These cause serious internalstresses which serve to weaken the tooth structure and lead to itspremature failure in service. Additionally, the results of heattreatment essential to the desired hardening for greater wear andabrasion resistance vary widely and these constitute another importantfactor deterrent to long service life.

Still another deficiency of prior tooth design is the lack of suflicientrelief on its underside with the result that the tooth rides on andslides over the top surface of freshly completed ripping similarly to asled runner on snow and this action prevents the tooth from penetrating.

Other shortcomings of prior designs concern the contour of the shankemployed to seat the tooth. Thus prior designs typically employ amassive shank structure terminating at its lower end in aforwardly-projecting relatively small cross-section triangular nosepiece over which the tooth telescopes. This nose piece must be keptsmall to avoid the need for a tooth of excessive angle, size and cost.The brutal stresses to which the assemblies are subjected must betransmitted across the connection of the nose piece with the shank.Owing to the small dimensions imposed on the shank structure by thetooth design, it is common experience for the nose piece to break offeither at its juncture with the shank proper or in the area of the holefor the tooth retainer means which hole or passage weakens the nosepiece structure.

Still Aanother shortcoming of prior nose piece designs is the provisionof surfaces thereon intended to be complemental to the interior surfacesof the hollow tooth. Imperfections and tolerance variations in both ofthese interitting sets of surfaces unavoidably lead to ill-fittingteeth; nonuniform distribution of stresses on the two structures;malfunctioning, if not nonfunctioning, of the retainer pin; loss ofteeth in use; and the premature failure and loss of the tooth, shank,nose piece, and retainer pins while the ripper is in use.

Another general source of dissatisfaction in prior tooth and shankassemblies involves the retainer means provided for holding the teethdetachably assembled to the shank. A great variety of designs lhave beenproposed heretofore but all fail to meet desirable objectives. Brutalforces are involved and only the most rugged type of structure capableof withstanding extreme shock loads and the most severe corrosion andabrasion conditions can be tolerated. Threaded fasteners of any typehave long been considered unacceptable for many reasons Well known tothose skilled in this art. Many attempts have been made to providecooperating retainer members depending upon resiliency ,of theconstituent materials in combination with interlocking congurations ofthe tooth and shank to hold the parts assembled, yet capable of beingdisassembled and reassembled with a minimum of difficulty and loss oftime. For the most part, proposals utilizing resiliency of eithermetallic or nonmetallic materials, while overcoming certain defects ofother constructions, are nevertheless subject to other shortcomingssought to be obviated by the present invention.

The present invention avoids the foregoing and other shortcomings ofprior designs in a simple and highly efficacious manner. For example,both the ripper assembly and the traction vehicle employed in its useare so o constructed as to take advantage of very substantial forcesavailable as the new ripper is advanced through the terrain to increasethe traction effectiveness of the traction vehicle. Thus, the greaterthe load forces acting on the ripper tooth the greater is the availabletractive effort because substantial portions of forces acting o nthetooth act to increase the weight of the traction vehicle therebyincreasing its tractive effectiveness rather than to decrease it astypically occurs in prior designs. As herein illustrated, this isaccomplis-hed using a parallelogram linkage to interconnect the ripperframe proper with a forward portion of a crawler type traction vehicleand including suitable locking means for anchoring this linkage rigidlyin a desired adjusted position. The locking means may comprisehydraulically operated cylinder means having one end pivotally anchoredto the tractor frame and the other end to the linkage.

The invention ripper assembly just described includes a special toothand mounting shank so arranged and contoured as to be self-penetratingeven in the hardest formation until further penetration is precluded byuse of the lock-out mechanism. The tractive effectiveness of the vehicleincreases automatically as penetration of the tooth increases therebyproviding simple means for loading the vehicle to a maximum degreeconcurrently with utilization of the weight of ripped material toincrease effective traction. Once this maximum effective operating depthis ascertained the ripper can be locked rigidly in this operatingcondition as it continues to move forward in maximum efficiencyoperation.

The parallelogram linkage assures support of the ripper tooth or teethat the proper and most efficient operating angle irrespective of thedepth at which it is desired to operate. Closely associated with thisfeature is the design of the underside of the tooth and supporting shankin such manner as to preclude the possibility of these surfaces ridingon the newly formed surface of unripped material. Adequate clearancebetween these opposed surfaces assures the continu-ance f this highlyimportant condition as the tooth wears in service.

The ripper tooth itself includes many novel features as does thesupporting shank. The tooth of this invention has no hollow portions andis contoured with maximum attention to avoid heat reservoirs sodetrimental to the uniform and proper heat treatment of the tooth withsubstantial no locked-in internal stresses. To this end the tooth has anelongated arcuate main body slab provided along its opposite upperlateral edges with integral mounting flanges positioned closely againstthe opposite sides of a massive slab-like mounting shank. Substantiallyonehalf of the forward portion of the main body of the tooth isunsupported and extends downwardly and forwardly from the foremostcorner of the shank. This tip end is specially contoured and includes aplurality of edges and faces so disposed to the horizontal as to producemultiple cleavages into the formation being ripped along predeterminedshear planes selected for maximum eiciency ripping. These include edgesand surfaces disposed to shear the formation horizontally immediately inadvance of the path of travel as well as laterally to either sidethereof and additionally, in radial planes diverging upwardly from thetoe of the tooth. These shear planes continue to be opened progressivelythrough the formation well in advance of the tooth itself with theresult that material passing rearwardly over the surfaces 0f the toothis loose and `acts on the tooth under a pressure imposed largely by itsown weight with the result that wear and abrasion on the tooth surfacesis reduced to a minimum.

Closely associated with this matter of reduced wear on the tooth toe isthe fact that the surface of the main body rearward of the toe isrelieved to a slight extent. Under moist operating conditions thisrelieved area becomes packed with wet material to provide a protectivelayer safeguarding the tooth itself against Wear so long as the layer ispresent. Even under dry conditions wear on the surface is greatlyreduced by reason of the relieved condition.

The upper end of the main body is beveled upwardly and rearwardly andseats within a complementally shaped notch provided on the forward faceof the supporting shank. Accordingly, much of the pressure imposedacross the pointed end of the tooth is transmitted by compressive actionalong the body and upwardly and into the shank thereby materiallyreducing the load required to be absorbed by the lower tip end of theshank.

Featured also by the invention is novel foolproof highstrength retainerpin means of unique shape. This retainer pin assembly is formed in twoparts of massive cross-section one of which is much thicker than theother and is provided at its opposite ends with lugs projecting acrossthe opposite rim ends of a seating bore therefor crosswise of the shank,The other retainer member is bowed lengthwise of itself and is made ofhighly tempered resilient material capable of storing high-energytensile forces for long periods while in assembled condition. Both pinsare provided with facing flat surfaces which taper in oppositedirections to facilitate 4assembly within the shank bore and cooperatingto facilitate storing of the 4aforementioned tensile stresses which areutilized to hold the ripper tooth firmly seated at all times, andadditionally, to provide powerful frictional engagement between certainsurfaces to prevent disassembly of the retainer pin means.

Featured also by the retainer pin means is the noncircular shape of thereceiving openings for the retainer means and the slightly offsetregistry of the openings in the tooth anges with the shank bore in suchmanner that the pins in assembled stressed condition, are effective tourge the tooth upwardly and rearwardly against the forwardly slopingtooth seat formed on the shank. Positive and accurate seating of thetooth in this position is further facilitated and assured by reason ofprovision Afor lateral movement of the pins relative to one anotheralong their mid-length fulcrum to provide automatic self-centering andaccommodating compensation for tolerance variations in the severalcomponents; additionally accurate seating is facilitated by relief ofthe seating face on the shank in such manner as to provide two seatingpads crosswise of the shank edge.

Still another feature is the provision of a protective boot for theshank embracing the forward edge and side faces of the shank.

This protective boot is shaped to interlock with the upper perimeteredges of the tooth with the result that the retainer pin for the toothserves additionally to aid in holding the boot in its normal operatingposition. Providing further support for the boot are one or more lightfastener means constructed to hold the `boot in position while the toothitself is being removed and reassembled and also supplementing the toothretainer pin in holding the boot in assembled position.

These and other more specific objects will appear upon reading thefollowing specification and claims and upon considering in connectiontherewith the attached drawing to which they relate.

Referring now to the drawing in which preferred embodiment of theinvention is illustrated.

FIGURE 1 is -a side elevational view showing essential details of onepreferred embodiment of the invention ripper operatively associated witha crawler type traction vehicle while in the process of ripping a rockformation;

FIGURE 2 is a fragmentary longitudinal view on a large scale takenthrough the forward end of the ripper tooth;

FIGURE 3 is a transverse sectional view taken along line 3 3 on FIGURE 2showing typical cleavage planes as viewed crosswise of the ripper tooth;

FIGURE 4 is a fragmentary side elevational view on an enlarged scalethrough the lower end of the invention ripper shank and tooth assembly;

FIGURE 5 is a fragmentary exploded view of FIG- URE 4;

FIGURE 6 is a fragmentary transverse view through the tooth taken alongline 6-6 on FIGURE 4;

FIGURE 7 is a top plan view of the tooth per se;

FIGURE 8 is a transverse sectional view taken along broken line 8-8 ofFIGURE 4;

' FIGURE 9 is a cross-sectional view taken along line 9-9 on FIGURE 8;and

FIGURE 10 is a cross-sectional view similar to FIG- URE 9 but showingthe larger of the retainer pins in the process of being installed.

THE STRUCTURE GENERALLY Referring initially more particularly to FIGURE1, there is shown a crawler tractor 10 equipped with the usual tracklaying treads 11. Suitably secured across the rear end of this tractionvehicle in a suitable massive ripper frame 12 preferably connected tothe vehicle through pairs of parallelogram linkages 13, 14 located alongeither side of the vehicle. The forward end of lower link 13 ispreferably connected to a suitable draft connection intermediate theopposite ends of the tractor, such as, the master central draft bar 16customarily provided on this type of vehicle. The forward end of theupper link 14 is connected to the main tractor frame as by means of abracket 17 and a pivot pin 18 supported thereby. The rear ends of thetwo links are similarly connected to pivot pin means provided atvertically-spaced points on ripper frame 12.

Manually controlled power-operated means for holding the ripper elevatedto an inactive position, such as indicated in the broken line showing ofFIGURE 1, comprises a pair of hydraulic cylinders 20 located alongeither side of the tractor. Their upper ends are pivotally connected tobracket 17 whereas the piston rod 21 of each is pivotally connected toone link of the associated parallelogram linkage. It will be understoodthat flexible hose connections 22, 22 extend from the opposite ends ofcylinders 20 to convenient control means accessible to the vehicleoperator and by which pressurized liquid can be supplied to andexhausted from the opposite ends of the cylinder as necessary to raiseor lower the ripper under load conditions and to lock it in any desiredretracted or operating position.

THE RIPPER TOOTH The ripper tooth, designated generally 35 forming aparticularly important component of the invention, is cast or forged inone piece from suitable material, as steel, and is heat treated in amanner well known to those skilled in this art to impart to itshardness, toughness and excellent wear and abrasion resistantqu-alities. As best appears from FIGURES 4 to 7 the tooth comprises anarcuate shaped main body 36 and a pair of identical side flanges 37, 37.Main body 36 is of substantially uniform thickness except that itsthickness is slightly greater through the heel portion 38 of its toe ortip 39. The upper end 40 of the main body is beveled at about a 45degree angle to seat within a correspondingly shaped notch 41 formedcrosswise of the upper end of seat 26 in shank 25. If desired and beforeheat treating the shank, surface 40, as well as those portions of therear side of the main body in seating contact with pads 42, 42 of shankface 26, may be given a light surface finish. Pads 42, 42 may also begiven `a finish to provide accurate seating surfaces for the tooth whenassembled to the shank.

Heel and toe portions 38, 39, respectively, of the ad- Vance end of theripper tooth, are specially contoured to serve important functions. Ingeneral, the tip end of the tooth tapers -downwardly transverselythereof as well as in a lengthwise direction. Its opposite lateral edges45, 45 Ialso taper toward the square cut nose end 46 and the lattertapers upwardly and rearwardly in two stages, the latter 47 of which isinclined less acutely to the vertical than the lower -substantiallyvertically disposed slower stage. The upwardly facing surfaces of thetip also include a pair of pitched planar surfaces 49 meeting along theupper longitudinal center of the tooth and a pair of relativelyacutely-inclined planar surfaces 50, 50 sloping downwardly from theremote lateral edges of the pitched planar surfaces 49, 49. The twopairs of surfaces 49, 50 may be viewed as having the shape of a hiproof.

The described toe surfaces, and particularly the longitudinal ridgestherebetween, together with the converging lateral edges 45, 45 and thesharp-edged nose piece 46, cooperate in producing concentrated stressesalong shear planes so disposed as to facilitate multiple cleavagesprogressing in predetermined directions in the formation being ripped.This will be best understood by reference to FIGURES 2 and 3 showing theprincipal planes of cleavage in a typical homogeneous rock formation.

Thus, referring to FIGURES 1 and 2, it will be `seen that onewedge-shaped cleavage proceeds forwardly in a horizontal direction fromthe forward end of the nose piece. Simultaneously, other planes ofcleavage proceed outwardly and upwardly, as will be best seen from FIG-URE 3. Thus, the forwardly tapering edges 45, 45 cooperate with theforward edge of the nose piece in extending the horizontal cleavage toeither side of the ripper tooth thereby greatly amplifying the cleavageinitiated by the nose of the ripper. At the same time the longitudnalridges between surfaces 49 and 50 as well as the central ridgelongitudinal of the nose piece form upwardly diverging cleavage planesextending at an angle to one another in the manner shown in FIGURE 3.

Initially very considerable power is required to initiate the planes ofcleavage but once these are started the shearing action through thebrittle rock proceeds rapidly under high mechanical leverage and isfurther facilitated by the powerful wedge lactions produced by thetapering surfaces 46, 47, 50 and 49 on rock passing over portions of thenose piece rearward of its advance end. Powerful camming action producedby these acutely inclined surfaces will, therefore, be understood ascooperating with the ridge edges themselves in a highly eilicient manneto cause the rock formation to break up as it flows smoothly rearwardlyover the tooth surfaces. Inasmuch as the rock normally breaks up inlarge pieces there is relatively slight contact with the tooth as therock flows therepast. For this reason, as well as the fact that the topsurface of the main body in the area overlying the rear end of the nosepiece is relieved or undercut, there is very little wear on the uppertwo-thirds of the main body. In fact, in most terrain, particularly whenmoist, the relieved surface of the tooth main body becomes coated with alayer of/compacted material with the result that no wear occurs to thecoated surface under these conditions.

Likewise the opposite sides, and particularly the under surface of thetooth, are not subject to any except slight wear owing to the design ofthe tooth and the ample relief provided rearward of its nose. Sideflanges 37, 37 preferably extend downwardly below surface 28 of theshank sulliciently to protect this surface from wear. The foremost lowercorner of the side flanges are contoured as indicated in order toprovide reinforcing at 53 (FIG- URE 4) for the nose piece andadditionally to provide a short skid for the tooth while withdrawingrearwardly from a ripping operation. It will also be noted that therelatively llat forward corner of the shank terminates in the generalarea of but above reinforcing webs 53. Accordingly, webs 53 will beunder-stood as acting as skids and additionally as reinforcing for thetooth at this point thereby preventing break-off of the advance end ofthe tooth under severe operation conditions.

THE RETAINING PIN MEANS Referring more particularly to FIGURES 5 and 8to 10,

there will be described the two-piece retaining means used to hold tooth35 forcibly and resiliently seated against pads 42, 42 and with itsupper beveled end 40 firmly pressed against shank surface 41. Thisretaining means comprises a relatively massive straight non-flexingmember 60 and a relatively smaller longitudinally-bowed resilient key61. These members have juxtaposed flat faces 62, 63, respectively,tapering in opposite directions in their assembled positions therebymaterially facilitating assembly and disassembly.

The retaining pins 60, 61 are mounted in a transverse opening or 'bore65 through the shank with their ends terminating in aligned openings 66,66 through tooth fianges 37, 37. It is pointed out and emphasized thattooth openings 66, 66 are slightly disaligned with the shank opening 65in a direction offset slightly forwardly from the center of openings 65.All openings preferably are generally elliptical in cross-section withthe major axis disposed substanF tially vertically. Openings 66, 66 areprovided with a radial notch 67 along their lower forward corners andwith a lowheight arcuate boss 68 projecting inwardly from theirdiametrically opposed corners. Notches 67, 67 accommodate very shortradial lugs 69 provided at the opposite forward corner ends of largerpin 60. As will be observed, particularly from FIGURES 4, 9 and 10 lugs69 are substantially smaller than the receiving notches 67 in the toothflanges or side walls. Accordingly, in the assembled condition of theparts, lugs 69 do not contact the tooth or interfere with its positionon the shank. The distance between the locking lugs 69, 69 is slightlygreater than the width of shank with the result that these lugs seatover the opposite rim edges of bore 65 in the manner best shown inFIGURE 8. The intervening side wall portions of member 61 conformgenerally to the elliptical shape of bore 65 and seat firmly againstthese surfaces in the fully as- Sembled position of the retainer pins asis best illustrated in FIGURE 9.

The bowed condition of locking pin 61 is best shown in FIGURE 8 fromwhich it will be observed that the flat surface 63 is providedtransversely of its mid-portion with a rounded rib 72 complemental to achannel 73 formed in flat surface 62 of pin 60. In the fully assembledposition of the pins rib 72 is seated in channel 73 and held underhigh-pressure contact therewith by reason of the highly stressed ortensioned condition of pin 61.

Rounded rib or fulcrum 72 and its cooperating channel 73, whichpreferably has a larger radius of curvature, not only serve to provideincreased assurance that the pins will remain fully and properlyassembled, but serve important aditional functions. For example, pin 61acts to distribute the powerful elasticity forces stored therein by theassembly operation in a fully equitable manner to both side walls of thetooth and in predetermined direction irrespective of wide variations inmanufacturing tolerances of the cast tooth and of the two retainer pins.It is of course self-evident that pin 61 is free to pivot about itsfulcrum axis as necessary to take care of tolerance variations in theradial height of bosses 68, 68 and equivalent variations of othersurfaces on the opposite lateral halves of the assembly. Equallyimportant is the fact that pin 61 is also free to shift to a limitedextent axially of fulcrum 72, that is transversely of the fiat surfaceof pin 60. This important capability provides compensation forvariations in the radial height of the end corners of bosses 68 andthereby enables pin 61 to shift sidewise in an automatic self-centeringmanner to a position wherein the load forces are delivered equitably tothe tooth and in a direction normal or substantially normal to the fiatsurfaces on the two pin members.

Another feature of the very powerful resilient locking pin 61 is thefact that its foremost end is rounded and tapered as indicated at 75whereas its opposite end 76 is relatively blunt and provides a strikingsurface for a sledge hammer used in forcing this pin into its assembledposition. The tapered end, being rounded on its upper side and somewhatthinner on its fiat side, is easily started into the wider openingprovided at the left-hand side of the assembly as viewed in FIGURE 8.Owing to the slightly misaligned condition of openings 65 and 66,additional room is available to facilitate assembly of the pins up tothe time the tapered end of pin 61 approaches entry into the second oneof openings 66. At this time its rounder outer surface contacts boss 68whereupon the pin is forced to straighten toward a straight linecondition toward flat surface 62 of pin 60. When it is finally drivenuntil its blunt end is flush with the surface of left-hand tooth flange37, it is in highly stressed condition, locking rib 72 is seated inchannel 73 and the exterior surfaces of the pin ends are in highpressure frictional contact with bosses 68, 68.

Under these conditions the massive pin 60 has substantially all of itsexterior surface in firm seating contact with the lower forward surfacesof shank bore 65 and out of contact at all points with the toothopenings 66. The reverse conditions are true as respects the highlystressed resilient pin 61 which is nowhere in contact with the shankwhile its opposite ends are in high pressure contact with tooth sidewall bosses 68, 68 in a manner urging the latter upwardly and rearwardlyat an angle of approximately 45 degrees to the horizontal as viewed inFIGURES 1 and 4. Accordingly, the beveled surface 40 across the upperend of the tooth main body is pressed against surface 41 of the shank.And in particular, the rear surfaces of the tooth main body are heldfirmly seated against pads 42, 42 of the shank seating surface. In thisconnection it is to be noted that the portion of tooth seat 26 betweenpads 42 is preferably relieved and out of contact with the tooth at alltimes.

ASSEMBLY AND OPERATION The assembly of the tooth is accomplished byplacing it astride the forward face of shank 25 and holding it in thisposition in any suitable manner while pin 60 is inserted into bore 65 byholding the same in the position generally indicated in FIGURE 10. Oncethe pin is properly centered lengthwise of the bore it can be lowereduntil its forward and lower side walls seat firmly against correspondingsurfaces of bore 65 with its lugs 69 seated loosely in notches 67 of thetooth side walls. The parts will then be in the position indicated inFIGURE- 9. Thereafter, the tapered forward end 75 of locking pin 61 isinserted from the lefthand side of the tooth as viewed in FIGURE 8. Thispin fits loosely in the opening until its forward end engages the toothside wall on the far or right-hand side of the assembly. Thereafter itmust be forced home by striking blunt end 76 with strong blows using aheavy hammer or sledge. This straightens and tensions pin 61 toward fiatsurface 62 of pin 60, the deflection being slightly greater just priorto full seating of locking rib 72 in groove 73. In its final assemblyposition, its opposite ends, like those of pin 60, will be substantiallyflush with the outer side walls of tooth flanges 37.

Under these assembled conditions pin 61 will be highly stressed andtooth 35 will be held powerfully and resiliently seated against pads 42and with its beveled surface 40 firmly seated against surface 41 of theshank notch.

It will also be observed from FIGURE 1 in particular that the sideflanges of the protective boot 30 are notched at 77 to conform generallywith the shape of the upper portion of the tooth. Accordingly, theretainer pins 60, 61 assume a principal portion of the load in holdingboot 30 against removal while the ripper is being backed through rippedmaterial. Accordingly, the cap screws 31 need not take a principalportion of this load, and relatively small size cap screws serve thepurpose of supporting the boot while tooth 35 is detached. During normalforward movement of the ripper through material undergoing ripping, theboot seats against the forward edge of the shank and imposes noparticular load on either cap screws 31 or the tooth retaining pin 60,61.

Disassembly of tooth 35 is accomplished by placing a proper sized punchagainst tapered end 75 of pin 61, and striking it with strong blows toforce it to the left (FIG- URE 8). Once the pin has been removed largerpin 60 may be withdrawn in the reverse manner of its assembly operation,it being understood that the tooth is suitably locked or otherwisesupported against its seat on the shank while the pin is being removed.

To place the ripper in operation, the operator of vehicle 10 operateshydraulic control valves, not shown, to release liquid from the lowerend of cylinder 20 and admit liquid to the upper end. The valves areleft in these positions as the vehicle moves forward and toe end 39 ofthe tooth begins penetrating the formation aided, if necessary, bypressure applied by cylinder 20. The weight of the ripper frame, aidedvery materially by the action of inclined surfaces 46, 49, and S0 aswell as by the camming action thereof, continues to force the rippertooth downwardly into the terrain. As the toothrpenetrates, the weightof the burden overlying the tooth becomes increasingly effective inforcing the tooth downwardly even in solid rock. This automaticself-penetrating action of the ripper assembly is very materially aidedby the aforedescribed action of the inclined surfaces and of the sharpedges along the perirneters of these faces in causing shearing andcleavage of the rock Well in advance of its tip.

As soon as the driver senses that the ripper has `penetrated to a properhigh-efficiency operating depth, he operates the hydraulic fluidcontrols to cut off flow to the opposite ends of the cylinders therebylocking the parallelogram linkage rigidly against movement in eitherdirection but principally against further extension of cylinders 20.While the ripper and its parallelogram linkage are so locked it will beapparent that major portions of the load forces acting on the tooth arechanneled back through links 13, 14 and the locking cylinders 20 andcommunicated to the tractor assembly to increase the tractive effort oftreads 11. In other words, the greater the load on tooth 35 the greateris the effective weight of the tractor, and the greater is the tractiveeffort applied by treads 11 to the terrain surface.

The terrain is progressively broken into major portions over a wide beltin the direction of travel, this width being dependent largely on thehardness of the formation since the shearing forces spread more widelyin brittle than in softer material.

' The wear on tooth 35 is appreciably less than in other teeth operatingin the same terrain and over the same distance.' Furthermore, this wearis found to take place generally evenly throughout surfaces 46, 49, and50 with the result that these surfaces tend to maintain their same shapeand relationship over prolonged periods of usage and as the tooth Vwearsback toward the lower corner of shank 25. Relatively minor wear occursalong the lower edges ofthe side flanges and over the'arcuate portion ofthe main body of the tooth rearwardly of camming surfaces 49. 50. It isfurther pointed out that the major load force acting on the tooth isassumed by the transverse forward end 46 and transmitted lengthwisethroughout the length of the tooth body and as a compressive force andis-delivered upwardly into the shank across the interface betweensurfaces 40, 41. These load forces neither tend to increase or decreasethe load or the tension stresses in the locking pin assembly and theycontinue to function with full efliciency to hold the tooth firmlyseated against pads 42 and surface 41 regardless of whether the tooth isunder load or free of load.

Owing to the efficient shearing action characterizing the inventiontooth in operation, the principal downward force on the tooth tip is theweight of the overlying rock. These forces are relatively smallcomparedto those acting against the transverse tip end of the tooth and, asexplained, these are 4transmitted upwardly placing the main body of thetooth under high compression rather than under bending stress. It is forthese reasons that the present tooth is designed to project forwardlyof,the shank by a far greater distance than heretofore. Likewise, it isfor this reason that the service life of the tooth is greatly prolonged.Furthermore, as wear occurs it will be appreciated from FIGURES l and 4that the clearance provided between the terrain and the underside of thetooth and of its flanges remains the same. In this connection it will beobserved that the lowermost edge of web 53 of the tooth flange and ofshank surface 28 both have a clearance angle of approximately fivedegrees with respect to the horizontal.

While the particular ripper apparatus and method of using same hereinshown and disclosed in detail is fully capable of attaining the objectsand providing the advantages hereinbefore stated, it is to be understoodthat it is merely illustrative of the presently preferred embodiment ofthe invention and that no limitations are intended to the details ofconstruction or design herein shown other than as defined in theappended claims.

I claim:

1. In combination, a rigid mounting shank for a tooth usefulrin diggingand ripping hard terrain, an opening of uniform cross-section extendingtransversely throughsaid shank near the lower end edge thereof, saidshank having a forwardly facing transverse edge notched across its upperend and shaped to seat the upper curvate end portion of a tooth, aone-piece steel tooth having an elongated curvate main body terminatingin a bluntly pointed forwardly projecting ripping end and an upper endshaped complemental to and seated in said shank notch, said main bodyportion including integral side flanges lying in parallel planes alongeither lateral edge of said main body and spaced to embrace the oppositesides of said shank, aligned openings through said side flanges ingeneral registry with said opening through the shank but offset slightlyforwardly from accurate registry with said opening, and retainer meansreleasably locking said tooth to said shank including a pair ofindependent and separate pin members of substantially different size andcross-sectional areas, the larger of said pin members being nonbendingstraight and shaped to seat against the juxtaposed surface along oneside of said shank opening and having a pair of radially disposed lugsat its ends spaced apart a distance slightly greater than the length ofthe opening through said shank and adapted to engage the rim edges ofsaid shank opening, and the second and smaller of said pin members beinglongitudinally bowed and of highly resilient material with itsmidportion bearing against the juxtaposed midportion of said first pinmember and the opposite sides of its end portions bearing against theedges of the openings through the tooth side flanges and acting to urgesaid tooth into fully seated position against the forward edge of saidshank, and said second pin member being adapted to be forcibly drivenendwise into assembled position only after said first pin member hasbeen installed and properly seated in said shank opening.

2. The combination defined in claim 1 characterized in the provision ofa one-piece channel-shaped protectiveV boot for forwardly facing edgeand sides of said shank in the area thereof overlying the upper end ofsaid tooth, said boot extending along the major length of said shank andhaving the lower end edges of its sides shaped complementally to andnested over the upper end of said tooth, and pin means extending throughsaid boot and into said shank and useful for supporting said boot onsaid shank while said tooth is being assembled and disassembled relativeto the shank.

3. The combination defined in claim 1 characterized in that the lengthof said tooth projecting beyond the foremost end of said shank is inexcess of one-third of the length of the 4main body portion of saidtooth and having an average thickness in a Vertical plane approximatingthe thickness of the remainder of said main body.

4. The combination defined in claim 1 characterized l 1 n that said sideflanges project slightly below the lower end of said shank and serve asglide surfaces effective to support said shank generally out of contactwith hard terrain undergoing working.

5. The combination defined in claim 1 characterized in that said openingthrough said shank is generally elliptical in cross-section with itsmajor axis substantially vertical and wherein said first pin me-mberoccupies the lower forward portion of said opening and wherein saidsecond pin member occupies the upper rearward portion of said openingwith its major tooth-retaining forces acting generally in a planeinclined upwardly and rearwardly along at an angle in the vicinity of 45degrees to the vertical.

6. The combination defined in claim 5 characterized in that in theassembled position of the defined components said first pin member islocked against endwise movement by contact of said lug with the sides ofsaid shank, and said rst and second pin members being held againstrelative endwise movement by interlocking boss and seating meanstherefor extending crosswise of said pin members at their mid-portions.

7. A ripper tooth adapted to be locked in position on theforwardly-facing arcuately-contoured recessed lower forwardly directedtransverse face of a supporting shank, said tooth having a wide longcurvate main body of generally uniform thickness and shaped to seatagainst said arcuately-contoured recessed face of said shank with itsupper end bearing against the juxtaposed upper edge of said recess andits lower end supported as a cantilever forwardly of said shank, saidmain body having a pair of flat generally parallel side flanges integralwith the opposite lateral edges of said main body along the upperportion thereof and essentially unattached to said main body along theother edges of said flanges, and said flanges having approximately thesame thickness as said main body whereby said tooth can be heat-treatedwithout risk of producing locked-in stresses arising from unequalcooling of different portions thereof during the quenching phase ofheat-treating, and aligned openings through said side anges for use inseating retainer pin means to hold said tooth assembled against thelower forward corner of a shank.

8. A ripper tooth as defined in claim 7 characterized in that theforward end of said tooth is generally straight and normal to the lengthof the tooth, and in that the opposite lateral faces are generallyplanar and converge upwardly along angles acute to a longitudinalvertical plane through said tooth and merge with the opposite ends ofsaid straight forward end.

9. A tooth as defined in claim 7 characterized in that said alignedopenings through said side flanges are noncircular and generallyelliptical in shape with the major axis thereof extending generallyvertically in the normal operating position of said tooth, and saidopenings including a notch and a boss disposed generally diametricallyopposite one another in a plane inclined upwardly and rearwardly at anacute angle to the vertical.

10. The combination defined in claim 7 characterized in that the mainbody and side flanges of said tooth are of generally the same thicknesswhereby the heat treatment of said tooth does not create areas ofunequal stress and strains caused by unequal cooling of said tooth whileundergoing heat treatment.

11. The combination defined in claim 7 characterized in that thecomplementally-shaped intert renders said retainer pin means effectivein combination with said pin means to hold said boot in assembledposition on said shank.

12. A ripper tooth as defined in claim 7 characterized in that theforward upwardly directed face of said tooth adjacent the lower endthereof has a ridge extending centrally of its length and taperingdownwardly to either lateral edge of said tip.

13. A ripper tooth as defined in claim 7 characterized in that the saidstraight forward end of the tooth merges with a beveled surface slopingupwardly and rearwardly toward the ridge of said pitched surface.

14. A tooth as defined in claim 7 characterized in that the uppertransverse edge of said tooth is beveled upwardly and rearwardly anddesigned to fit within a complementally-shaped transverse notch acrossthe forward edge of a mounting shank for said tooth.

15. A tooth as defined within claim 7 characterized in that said sideanges extend downwardly along the opposite sides of said main body toreinforce and support the tip end of said tooth and have lower edgesadapted to serve as glide shoes for said tooth effective to elevate thetooth while being moved rearward out of a ripping operation.

16. A retainer pin assembly for use in locking a digging member to asupporting shank of the type having an opening therethrough of generallyuniform cross-section, said assembly comprising a pair of elongatedindependent pins of widely differing cross-sectional areas each having agenerally flat surface extending lengthwise thereof, the larger pinhaving a short lug projecting radially from its ends and away from thatpins fiat surface, the smaller pin being bowed lengthwise thereof in adirection away from the fiat surface of the larger pin and adapted tohave its flat `midportion bear against the flat midportion of saidlarger pin, and said smaller pin being highly resilient and adapted tohave its exterior end surfaces under high loading pressure when saidassembly is forcibly assembled in generally aligned openings ofcooperating size formed in a digging member and in a supporting shanktherefor.

17. A retainer pin assembly as defined in claim 16 characterized in thatsaid assembly is shaped to occupy aligned openings through a diggingtooth and a mounting shank therefor which openings are generally ofelliptical shaped and wherein the flat faces of said two pins liegenerally at an acute angle to the major axis of said ellipticalopenings, and one of said pins being free to shift laterally of theother longitudinally of the fulcrum axis between the two pins to assureequitable distribution of forces when the pins are assembled in anoperating environment.

18. The combination defined in claim 16 characterized in that theforwardly projecting one-half end portion of said tooth lies generallyin a plane below the lower end of said shank.

19. The combination defined in claim 16 characterized in that each ofsaid pins have their respective generally flat surfaces tapering inopposite directions lengthwise of said pins and being adapted forassembly in a supporting shank with their respective smaller endspositioned remotely from one another.

20. A retainer pin assembly as defined in claim 16 characterized in thatone set of remotely positioned ends of said pins is thicker than theother set of ends and in that said smaller pin is tapered at one end tofacilitate the assembly thereof.

21. A retainer pin assembly as defined in claim 16 characterized in thatsaid pins have a complementally shaped hump and recess crosswise of themidportions of their fiat faces cooperating to lock said pins in theirnormal assembled position and cooperating to permit said pins to pivotrelative to one another to compensate for irregularities and variationsin manufacturing tolerances.

22. A ripper tooth having a long arcuate main body having a pair ofgenerally parallel side mounting lianges integral with its oppositelateral edges near one end of said body, the opposite tip end of saidmain body having a ridge extending lengthwise of the top side thereofand including downwardly and laterally diverging surfaces extendingacross the major width of said main body and merging along the remoteedges thereof with acutely inclined planar surfaces forming the Oppositelateral faces of -the tip end of said tooth, and the transverse tip endOf Said {Ila-ill bOdy having a planar surface sloping up- 13 wardly andrearwardly toward the opposite upper end of said main body.

23. A ripper tooth as defined in claim 22 characterized in that theupper transverse end of said main body projects upwardly in a generallyvertical direction when said tooth is supported in its normal rippingposition, and said upper end being beveled upwardly and rearwardly awayfrom said tip end and adapted to seat snugly with the seating notch of asupporting shank for said tooth.

24. A ripper tooth as defined in claim 22 characterized in that the topsurface of said main body rearward of said ridge and of the slopingsurfaces immediately to either side thereof are relieved to form anupwardly and forwardly facing curvate surface serving as a moldboard forripped material fiowing rearwardly along the top surface of said tooth.

25. A ripper tooth as defined in claim 24 characterized in that theacutely and upwardly tapering opposite sides of the tip end of saidtooth converge toward one another lengthwise of said main body andtoward the front end thereof and are effective in parting the materialbeing ripped and in forcing the tip end of said tooth downwardly as thetooth is advanced into terrain undergoing ripping.

26. In combination, a tractor having a main frame supported on a pair ofpower-driven track layers arranged along the opposite sides thereof,upright bracket meanssecured to, projecting upwardly from and formingpart ofthe mid-section of said main frame and located adjacent eitherlateral side of said tractor, a ripper frame extending across the rearend of said tractor, parallelogram linkage means along either side ofsaid track layers and having their forward ends pivotally connected tovertically spaced points in the mid-section of the tractor frame and tosaid upright bracket means and their rear ends pivotally connected tosaid ripper frame, a pair of hydraulic cylinder means arranged totransfer load forces acting on said parallelogram linkage means into themid-section of said tractor frame to increase the traction of said tracklayers with the underlying ground, said hydraulic cylinder means havingtheir upper ends pivotally connected to the upper end of said uprightbracket means and their lower ends to said parallelogram linkage meansforwardly of the rear ends of said track layers, said ripper framehaving a ripper tooth shank projecting downwardly therefrom with aripper tooth detachably connected to the lower forward corner thereof,

said tooth having a downwardly and forwardly slopingV tip end extendingdownwardly and forwardly beyond the lower end of said shank andeffective as said tractor moves forwardly to penetrate deeper into theterrain automatically as the tooth breaks the overlying terrainupwardly, and the penetrating capabilities of said tooth being effectivethrough said parallelogram linkage means, said bracket means and saidhydraulic cylinder means to force the track-laying part of said tractorinto firmer and more powerful traction with the underlying surface ofthe terrain.

27. In combination, a generally vertically disposed ripper shank havinga slightly curved lower forward edge and a relatively wide parallel facelying normal to said curved forward edge, the lower end of said shanklying at an acute angle to the horizontal and tapering upwardly andrearwardly from its foremost corner, a ripper tooth having a longarcuate main body provided along its opposite upper sides with integralmounting fianges adapted to fit loosely over the lower forward corner ofsaid shank and a tip end projecting downwardly and forwardly of saidlower shank corner, the back surface of said tooth being curvedgenerally similarly to the juxtaposed surface of said shank, and one ofsaid surfaces having accurately finished seating pads across itsopposite ends and spaced outwardly from the intervening portions of thatsurface whereby the load forces applied to said ripper tooth whenengaged in a ripping operation are transmitted to said shank essentiallythrough said seating pads.

28. The combination defined in claim 27 characterized in the provisionof an opening through the lower end of said shank in slightly offsetalignment with a pair of openings through the side fianges of saidtooth, a pair of retainer pins assembled in said openings cooperating tolock said tooth assembled to said shank, one of said pins being bowedlengthwise thereof with its opposite ends bearing against the edges ofthe openings in said tooth side walls in a direction to hold one of saidcurved surfaces firmly seated on the accurately finished seating pads ofthe other arcuate surface and the upper end of said main body pressedinto the V-notch of said shank.

29. The combination defined in claim 27 characterized in the provisionof a V-shaped notch crosswise of said shank at the upper end of saidarcuate surface, and the upper end of the main body of said tooth beingshaped and positioned to seat in said notch when mounted on said shank.

30. That method of ripping hard terrain and utilizing the weight offreshly ripped material to increase the effective traction forces of atractor hauling a ripper which method comprises, utilizing parallelogramlinkage means to couple the forward end of terrain ripper means to themid-length of the frame of a track laying tractor having a frame,attaching a ripper tooth to the lower forward end of a ripper shankforming part of said ripper means, providing an adjustable rigiddraft-transmitting connection between the ripper means and themid-length of the tractor frame, utilizing said adjustable draftconnection and said parallelogram linkage means to hold said rippertooth at a desired penetration level in terrain being ripped and totransfer onto the mid-length of the tractor frame a major portion of theweight of broken terrain overlying said ripper tooth as the tractor ispropelled forwardly, and utilizing the forces and weight of brokenterrain acting on the ripper tooth as the tractor is propelled toincrease the tractive effectiveness of the tractor.

References Cited UNITED STATES PATENTS 2,985,973 5/ 1961 Struemph172-699 3,002,574 10/ 1961 Padrick 172-699 3,024,851 3/1962 Harres172`464 X 3,085,635 4/ 1963 Livermore 37-142 X 3,116,797 1/ 1964 Launderet al. 172-699 X 3,121,289 2/ 1964 Eyolfson 37-142 3,196,956 7/ 1965Ratkowski 172-699 X 3,225,467 12/1965 Troeppl 37-142 VERNEST R. PURSER,Primary Examiner. CHARLES E. OCONNELL, Examiner.

30. THAT METHOD OF RIPPING HARD TERRAIN AND UTILIZING THE WEIGHT OFFRESHLY RIPPED MATERIAL TO INCREASE THE EFFECTIVE TRACTION FORCES OF ATRACTOR HAULING A RIPPER WHICH METHOD COMPRISES, UTILIZING PARALLELOGRAMLINKAGE MEANS TO COUPLE THE FORWARD END OF TERRAIN RIPPER MEANS TO THEMID-LENGTH OF THE FRAME OF A TRACK LAYING TRACTOR HAVING A FRAME,ATTACHING A RIPPER TOOTH TO THE LOWER FORWARD END OF A RIPPER SHANKFORMING PART OF SAID RIPPER MEANS, PROVIDING AN ADJUSTABLE RIGIDDRAFT-TRANSMITTING CONNECTION BETWEEN THE RIPPER MEANS AND THEMID-LENGHT OF THE TRACTOR FRAME, UTILIZING SAID ADJUSTABLE DRAFTCONNECTION